What type of stability is described by the ability of a power system to maintain equilibrium after a disturbance?

The concept of stability in power systems is critical for maintaining reliable operation. Transient stability refers to the ability of a power system to maintain synchronism and return to a stable operating condition following a disturbance, such as a sudden change in load, a fault, or the loss of a generator. This type of stability is primarily concerned with the immediate response of the system to disturbances and its ability to reach a new equilibrium.

During disturbances, transient stability is assessed by analyzing how quickly and effectively the system can stabilize its voltages and maintain the synchronism of generators. The focus is on the dynamic behavior of the system's components over a relatively short time frame—typically seconds to a few minutes.

The other types of stability mentioned relate to different aspects of system performance. Voltage stability deals with the system's ability to maintain adequate voltages across the network following a disturbance, while frequency stability pertains to the system's ability to maintain a steady frequency, particularly after major contingencies. Steady-state stability is concerned with the power system's ability to return to equilibrium after small, gradual changes rather than sudden disturbances. Each of these stability types addresses different scenarios, but the ability to maintain equilibrium post-disturbance is the essence of transient stability.